Accelerator in vulcanizing rubber compounds



BENJAMIN E. LORENTZ,

MENTS, '10 R. 'I. VANDERBILT COMPANY, OF

NEW YORK.

OF FORT WAYNE, INDIANA, ASSIGNOR, BY MIESNE ASSIGN- NEW YORK, N. Y., A CORPORATION OF ACCELERATOR IN VULCANIZING RUBBER COMPOUNDS.

No Drawing.

To all whom it may concern:

Be it known that I, BENJAMIN E. LORENTZ,

a citizen of the United States, residing at Fort Wayne, county of Allen, State of Indiana, have invented certain new and useful Improvements in Accelerators in Vulcanizing Rubber Compounds, of which the following is a full,olear, concise, and exact description.

The object of my invention is to improve the vulcanization or" rubber compounds by the addition thereto of certain organic substances which. through their catalytic or other action greatly reduce the time required for vulcanization while at the same time improved results are accomplished with the addition of smaller quantities of the accelerator or catalyzer than has heretofore been possible.

to the present time it has been considered that organic. compounds must be strongly basic in character, such as amines and ammonias, in order to constitute effective catalytic agents in the vulcanization of rubber, and many such compounds have been advocated, especially those which have a dis- This dissociation point has distinguished the strong bases, such as aliphatic amines, from weak bases, such as aniline oil and similar aromatic substances.

I have discovered, however, that comounds' known as tetra-substituted thiuram- 85 disulphides, in which the substituting groups may be radicals of either the aliphatic or aromatic series or both together are accelerators of particular effectiveness. These are produced by the oxidization of salts of alky- 40 lated dithio-carbamic acids by iodine, bromine,hydrogen peroxide or potassiumv persulphate, according to the formula:

The substances, particularly the tetra-substituted compounds of which tetramethyl thiuramdisulphide is an example, are capable of being heated to a relatively high de 50 gree without decomposition. They are not basic in character and are decomposed neither by kalies, and

sociation constant greater than the action of dilute acids nor aldo not combine with them. They Specification of Letters Patent.

Patented Apr. 18, 1922.

Application filed March 30, 1920. Serial No. 369,883.

are insoluble in water and have a definite crystalline form and definite melting points. They are essentially different in character and properties from the condensation products of dimethyline with carbon disulphide, known as dimethylammoniumdimethyldithiocarbamate, which has been used to some extent as an accelerator.

In general my improved catalyzers, are prepared by condensing an amine, preferably secondary amines, such as monomethylaniline, dimethylamine, etc., with carbon disulphide in aqueous or alcoholic solutions and then oxidizing the resulting product with any suitable oxidizing agent of which iodine, bromine, hydrogen dioxide, are examples. The resulting. com ound has the structure as indicated by R N. S.S.S.CS.NR

S :(E-NR When the radical R is substituted by CH the latter becomes Szfl-N-(CHQ,

rubber the following formula is given:

Crude rubber 100 lbs. Zinc oxide lbs. Sulphur 4 lbs. Tetramethyl thiuramdisulphide 2 oz.

Curing in the mold is continued for fifteen minutes at 280 F.

The very small quantity of the accelerator that is necessary and the reduced amount 0 sulphur made possible, together with the short time required in vulcanization, makes my improved accelerator particularly ecoomical and effective in rubber manufactures and at the same time improves the quality of the product.

proportion of ingredients for various proportions and other ingredients may be used with my improved accelerator, as will be understood by those skilled in the art, without departing from the spirit and. scope of my invention.

What I claim and desire Letters Patent is:

1. A vulcanized rubber compound containing before vulcanization a vulcanizing agent and a tetra-alkylated thiuramdisulphide, in which the substituting groups are hydrocarbon radicals.

2. A vulcanized rubber compound containing before vulcanization a vulcanizing agent and tetra-alkylated thiuramdisulphide.

3. A vulcanized rubber compound containing before vulcanization a vulcanizing agent and 'tetramethyl thiuramdisulphide.

4. An accelerator as an ingredient in the process of vulcanizing comprising a tetraalkylated thiuramdisulphide in which the to protect by substituting groups are hydrocarbon radi-- cals.

5. An accelerator as an ingredient in the process of vulcanizing comprising a tetraalkylated thiuramdisulphide.

6. An accelerator as an ingredient in the process of vulcanizing, comprising tetramethyl thiuramdisulphide.

7. The process of making rubber articles which comprises mixing with raw or crude rubber, a vulcanizing agent, and an accelerator comprising a tetra-alkylated thiuramdisulphide, in which the substituting groups are hydrocarbon radicals, and heating the resulting compound to vulcanize the same.

8. The process of making rubber articles 7 and an alkylated thiuramdisulphide.

' BENJAMIN E. LORENTZ. 

